MARC DROUIN et al. 2087 C7--C15 C8--C9 C8--CI7 C8--C22 C9---C10 C10----C11 C2--C I---C 14 C2---C I---C 18 C2---C 1---C20 C 14---C I---C 18 C14---C 1--C20 C 18----C 1----C20 C 1--C2---C3 C2---C3--C4 C3---C4---C5 C4---C5---C6 C5---C6---C7 C6--C7---C8 C 8---C7---C 15 C7---C8---C9 C7--C8--C 17 C7---C8--C22 C9--C 8---C 17 C9--C8--C22 C 17---C8---C22 C8---C9---C I 0 C9--C I 0---C 11 CI0---CI 1--C12 C 15---C7--C8---C 17 C8--C7--C15--C 16 C7--C8---C 17---C 16 C7--C 8---C 17---02 .551 (15) C20--O7 1.205 (13) .523 (14) C20---O8 1.323 (13) .539 (15) C21--O8 1.435 (16) .540(13) C22--O3 1.194(13) .521 (13) C22~O4 1.316(13) .502 (14) C23---O4 1.465 (13) 12.7(8) CI0--CI 1---O1 121.9(9) 12.8(8) C12---C1 I--O1 122.1 (10) 107.5(9) C11---C12--CI 3 112.6(9) 108.4(9) C12--C13--C14 112.4(9) 110.2(8) C1--C14--CI3 114.1 (8) 105.0 (8) C7--CI5--C16 102.3 (8) 113.4(8) C 1 5 ~ 16------C 17 108.2(10) 125.7 (10) C8---C17---C16 108.7 (9) 124.4 (10) C8--C17--O2 125.3 (10) 126.5 (10) C16---C17--O2 125.9 (11) 128.2 (9) C I---CI 8---O5 120.2 (10) 113.9(8) CI--C18---O6 113.4(10) 105.7 (8) O5---C 18--O6 126.4 (I0) 116.0 (7) C 1---C20---O7 126.3 (9) 102.9(8) C 1---C20---O8 111.2(9) I11.1 (8) O7--C20---O8 122.4(10) 112.6 (8) C8--C22--O3 123.6 (9) 107.8 (8) C8---C22--O4 111.8 (9) 105.9 (7) O3---C22--O4 124.6 (9) 116.3 (8) C22--O4---C23 116.5 (9) 112.3 (8) C18--O6--C19 109.5 (10) 116.0 (9) C20--O8--C21 117.5 (9) -30.8 (6) C7--C15---CI6---CI 7 -26.0 (6) 35.3 (6) C15--C16--C17--C8 7.4 (5) 14.6(6) C 15---C 1 ~ 17---O2 -176.1 (14) - 162.0 (12) Marinier, A. & Deslongchamps, P. (1988). Tetrahedron Len. 29, 6215- 6219. Michel, A., Drouin, M., Michel-Dewez, N., Roughton, A. & Des- longchamps, P. (1991). Acta Cryst. C47, 1032-1036. Michel, A., MicheI-Dewez, N., Roughton, A., Springer, J. P. & Hoogsteen, K. (1989). Acta Cryst. C45, 932-935. Sheldrick, G. M. (1993). SHELXL93. Program for the Refinement of Crystal Structures. University of G6ttingen, Germany. Stork, G., Winkler, J. D. & Saccomano, N. A. (1983). Tetrahedron Len. 24, 465-468. Acta Cryst. (1996). C52, 2087-2090 Glycyl-L-Leucyl-L-Tyrosine Dihydrate 2-Propanol Solvate BJORN DALHUS AND CARL HENRIK GORBrrZ Department of Chemistry, University of Oslo, PO Box 1033, Blindern, N-0315 Oslo, Norway. E-mail: bjornda@kjemi. uio.no (Received 8 November 1995; accepted 12 February 1996) For both compounds, data collection: DATCOL NRCCAD (Le Page, White & Gabe, 1986); cell refinement: TRUANG NR- CCAD; data reduction: DATRD2 NRCVAX (Gabe, Le Page, Charland, Lee & White, 1989); program(s) used to solve struc- tures: SOLVER NRCVAX. Program(s) used to refine structures: SHELXL93 (Sheldrick, 1993) for (I); LSTSQ NRCVAX for (II). For both compounds, molecular graphics: ORTEPII (Johnson, 1976) NRCVAX. Software used to prepare material for publi- cation: SHELXL93 for (I); TABLES NRCVAX for (II). Lists of structure factors, anisotropic displacement parameters, H- atom coordinates and complete geometry have been deposited with the IUCr (Reference: PT1020). Copies may be obtained through The Managing Editor, International Union of Crystallography, 5 Abbey Square, Chester CH1 2HU, England. Abstract The asymmetric unit (CI7H25N3Os.C3H80.2H20) con- sists of two crystallographically independent peptide molecules, A and B, with different conformations, X~ being trans and gauche- for the Leu residues in mol- ecules A and B, respectively. The backbone conforma- tion of both peptide molecules resembles that of the /3-pleated sheet arrangement found in proteins. Compar- ison with two other structures containing the tripeptide Gly-L-Leu-L-Tyr reveals almost identical molecular con- formations, and in one instance also a common packing pattern. References Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358. Crevisy, S., Couturier, M., Dugave, C., Dory, Y. L. & Deslongchamps, P. (1995). Bull. Chim. Soc. Fr. 132, 360-371. Deslongchamps, P. (1991). Aldrichimica Acta, 24, 43-56. Drouin, M., Lamothe, S. & Michel, A. (1992). Acta Cryst. C48, 2151- 2154. Gabe, E. J., Le Page, Y., Charland, J.-P., Lee, F. L. & White, P. S. (1989). J. Appl. Cryst. 22, 384-387. Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA. Lamothe, S., Ndibwami, A. & Desiongchamps, P. (1988). Tetrahedron Lett. 29, 1639-1640. Larson, A. C. (1970). Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, pp. 291-294. Copenhagen: Munksgaard. Le Page, Y. & Gabe, E. J. (1979). J. Appl. Cryst. 12, 464-466. Le Page, Y., White, P. S. & Gabe, E. J. (1986). NRCCAD. An Enhanced CAD-4 Control Program. Proc. Am. Crystallogr. Assoc. Hamilton Meet. Abstract PA23. Comment As part of a project dealing with the X-ray structures of tripeptides with non-Gly residues in the mid-position, we have crystallized Gly-L-Leu-L-Tyr as the dihydrate 2- propanol solvate (I). The structures of Gly-L-Leu-L-Tyr 2.5-hydrate dimethyl sulfoxide (DMSO) solvate (Wu, Tinant, Declercq & Van Meerssche, 1987; Subramanian & Parthasarathy, 1987) and the copper complex of the same peptide (Franks & van der Helm, 1970) have already been described. 0 0 II [I NH + -- CH 2-- C -- NH-- CH-- C-- NH-- CH-- COO- .C 3 HsO. 2H20 I I CH~ CH~ f. CH~ CH OH (I) © 1996 International Union of Crystallography Printed in Great Britain - all rights reserved Acta Crystallographica Section C ISSN 0108-2701 © 1996